1. Field of the Invention
The present invention relates to a method of manufacturing laminated plates, pencil boards and/or shafts for writing utensils, drawing utensils or painting utensils.
2. Description of the Related Art
In connection with the present invention, laminated plates discussed below are particularly plates of layers which are connected to each other and are composed preferably of fibers or other particles of all types which can be compressed together, and whose components are connected to each other mechanically or by chemical additives.
Laminated materials generally are understood to be plates or other bodies of web-shaped or foil-shaped materials which are composed preferably of wood fibers, of other pulp or cellulose fibers or of other natural or synthetic fibers or powders and which have several layers or material webs.
When the laminated materials are present as compressed fiber plates, they may also form the base plate out of which are obtained a certain number of smaller boards or other base bodies for further processing, for example, by sawing, punching or cutting, wherein these boards or other base bodies may then be used, for example, for furniture or for manufacturing shafts of writing utensils.
The proposed laminated plates can also be used, for example, for manufacturing boards or so called pencil boards which usually are used as base bodies for the manufacture of pencils or color pencils and constitute intermediate products for this purpose which are conventionally present in solid state and the approximate size of several half pencils, for example, five to twelve or preferably seven to ten half pencils, from which, after riveting, gluing in the leads and connecting two complementary boards with each other, the final pencils are manufactured, wherein the shafts of these pencils are then made of these intermediate products.
In the case of mechanical pencils or other utensils for writing, painting or cosmetics, the manufacture of the shaft and the preparation of the receiving boards for the leads can also be effected, for example, by manufacturing such boards having the total shaft thickness and then providing the boards with the required bores and/or other perforations.
Conventional fiber plates, for example, so called compressed chip plates or wood fiber plates, are in those cases manufactured of compressed wood fibers or lignocellulose-containing fiber material. By applying heat, moisture, mechanical forces, particularly compressive forces and/or chemicals, the raw material containing the lignin, cellulose and hemicellulose is comminuted in defibrating plants into its fiber-like anatomic basic components in the form of individual fibers and fiber bundles.
In connection with the present invention, the writing utensils mentioned below are particularly utensils of all types for writing, drawing and painting, wherein the writing element of the utensils usually is a lead of a suitable writing or painting agent which is rigidly connected to the shaft.
However, the proposed shafts for writing utensils can also be used for those utensils for writing, drawing or painting whose writing elements are mounted so as to be axially movable and possibly even exchangeable in the shaft. These may be various mechanical writing utensils, such as ball point writing devices or wick writing devices of all types, fountain pens or also so called drop pens or fine lead pens with different clamping and/or feeding mechanisms. In the same manner, the writing utensil shaft of the above-described type is also suitable for manufacturing cosmetic pencils of all types and, thus, also includes those various products in which the lead placed in the shaft is constituted of a cosmetic preparation or contains a cosmetic preparation.
Fiber plates, such as compressed chip plates or also wood fiber plates, are generally not new in the art. For example, DE-OS 23 25 670, WO 94/25264, EP 518018 A1 and U.S. Pat. No. 5,346,930 disclose the use of digested fiber material, usually called cellulose, for manufacturing fiber plates. These fibers are usually manufactured from chips in accordance with the chemo-thermo-mechanical pulping method or CTMP method or the thermo-mechanical pulping method or TMP method. These fiber materials are prepared in water to form a so called pulp sludge and possibly after the addition of binding agents and/or other additives, are placed on the screen of a paper machine. After dehydration, the non-woven fiber fabric is received by a format roller and is further hydrated.
For the manufacture of shafts for writing utensils or of boards for manufacturing the shafts, fiber plates having a thickness of about 5.0 mm are required. This means that the fiber fabric must have such a thickness that, after complete drying and shrinkage, these final thickness dimensions are reached. Since this can essentially not be achieved by using a single layer, several layers are produced and placed on the format roller. Consequently, the final fiber carpet is composed of several layers, preferably four to forty layers. Once the desired number of layers has been reached on the format roller, the material extending beyond the length of the roller is cut or separated and the carpet material is unwound over the length of the roller. The fiber carpet which is then composed of individual layers can now be further partially dehydrated and calibrated by being passed through a nip.
For completely dehydrating or drying the fiber carpet it travels through a drying tunnel. The fiber carpet can also be treated to reach its final properties by hot pressing in a heated wet press.
The methods previously known in the art have the disadvantage that the products manufactured using these methods have without additional binding agents not a sufficient adherence between the individual layers because the non-woven connection alone usually results only in a weak connection and is frequently not stable.
When later processed by planing, milling, cutting or sharpening, etc., portions of the layers are torn out and deformations occur.
However, the use of binding agents has not been found very useful in this connection because most binding agents do not have a sufficient retention on the fiber surface or in the non-woven fiber fabric and are for the most part washed out during dehydration. Consequently, in addition to the deficient adherence of the layers, the washed-out binding agent causes significant presence to the environment or waste water and the attendant problems. When used with a high binding agent concentration necessary for a sufficient effectiveness, this results in relatively stable final products, however, the costs for their production are frequently not economically acceptable.
Shafts for writing utensils of laminated materials and methods for manufacturing such shafts or pencils, are also generally known in the art. Used as initial bodies for this purpose are particularly direct windings around the respective lead or also prefabricated boards of laminated fiber material. For example, DE-GM 90 01 243 and DE-OS 40 03 289 disclose the manufacture of shafts for writing utensils from a sheathing of web-like or foil-like layers of paper, wood or synthetic material. In this method, the foil-shaped webs which are arranged one above the other in several layers or are placed or rolled one above the other, are glued together in such a way that they result in a shaft which has a high bending stiffness and may be sharpened.
In the case of rolled sheathings this shaft may be formed of a web layer coated on one side with adhesive and rolled up. It is not disclosed how the individual particles of the foil are to be connected to each other. For gluing the individual foil layers together, wood glue or cold glue or dispersion adhesives, preferably polyvinyl-acetate adhesives or other synthetic material dispersions are proposed. Another principal problem of these methods is that they do not disclose anything concerning the usually required binding agents for the fiber connection and it is mentioned concerning the processing thereof that the rolling method using the indicated methods is very difficult to carry out and that it is also not clear how the laminated boards can be manufactured on a large scale.
Swiss Patent 204 257 and German Patent 856 110 additionally disclose the manufacture of shafts for writing utensils in which pencil boards are manufactured as intermediate products in such a way that solid wood foil layers having a thickness of about 0.05 to 0.25 mm are coated or impregnated with binding agent and are connected to form wood boards. In accordance with another embodiment, it is also possible to provide intermediate layers of wood dust if the product to be manufactured is to have a lighter weight. For this purpose, the wood dust is additionally scattered on to the wood foil coated with binding agent. The binding agent may be applied in liquid or solid form on to the foils and may additionally be mixed with softeners which are supposed to penetrate into the wood together with the binding agent in order to impregnate the wood.
The wood boards manufactured in this manner are then pressed, wherein it is possible to simultaneously press the grooves for the lead and a portion for the outer pencil profile. Since such profiling pressing methods are very difficult to carry out in industrial productions and are also expensive and the result additionally depends to a high degree also on the type of the wood being used, it is questionable whether the disclosed solutions have ever been useful or are now useful for producing useful results. In addition, the disclosed methods become more expensive because each profiled plate must be separately placed for pressing.
In the case of non-profiled pressed plates which are further processed in the manner of solid wood boards, it is also necessary to make sure that the fibers are directed in the same direction which makes it even more expensive to carry out this method.